The present invention relates to a motor having a rotor that employs a consequent-pole structure.
Conventionally, for example, as described in Japanese Laid-Open Patent Publication No. 9-327139, a motor having a rotor having a “consequent-pole structure” is known. The rotor having the consequent-pole structure includes a plurality of magnets arranged in the circumferential direction of a rotor core and functioning as one magnetic pole, and salient poles integrated with the rotor core and each arranged between adjacent magnets. The salient poles function as the other magnetic pole. In such a motor, since the number of magnets of the rotor can be reduced by half while performance deterioration is suppressed to a low level, the motor is advantageous in resource saving, cost reduction, or the like.
On a magnetic pole of a rotor having a consequent-pole structure as described in Japanese Laid-Open Patent Publication No. 9-327139, a magnet having a force (induction) of magnetic flux and a salient pole having no force of magnetic flux are mixed. For this reason, a magnetic imbalance easily occurs. This leads to deterioration of rotational performance such as an increase in vibration caused by, for example, generation of cogging torque.